CYP2D6 Genotypes and Breast Cancer Clinical Outcomes in the Indonesian Population

Summary

The utilization of tamoxifen is considerably high in Indonesia, with about 170,000 tamoxifen prescriptions filed in 2015. It is metabolized by the enzyme CYP2D6, resulting in its active metabolite, endoxifen, which has been proven to be effective in the prevention and treatment of breast cancer. Studies showed the CYP2D6 gene has more than 100 variants; some of which are linked with reduced drug activity, while others do not have any pathological implications. The metabolizer profile of these variants is generally grouped into Ultra-rapid, Normal, Intermediate, and Poor Metabolizers (UM, NM, IM, and PM, respectively). In our previous study (NCT04312347), the investigators recruited 150 breast cancer patients who were taking adjusted dose of tamoxifen daily based on their CYP2D6 phenotype. Although the investigators have measured the endoxifen level of the patients with adjusted treatment, the clinical outcomes of the study are not yet conclusive.

Timeline

Start

2021-01-01

Primary completion

2024-04-30

Completion

2024-06-30

Publications

• Background Braal CL, Jager A, Hoop EO, Westenberg JD, Lommen KMWT, de Bruijn P, Vastbinder MB, van Rossum-Schornagel QC, Thijs-Visser MF, van Alphen RJ, Struik LEM, Zuetenhorst HJM, Mathijssen RHJ, Koolen SLW. Therapeutic Drug Monitoring of Endoxifen for Tamoxifen Precision Dosing: Feasible in Patients with Hormone-Sensitive Breast Cancer. Clin Pharmacokinet. 2022 Apr;61(4):527-537. doi: 10.1007/s40262-021-01077-z. Epub 2021 Nov 17.
• Background Sanchez-Spitman A, Dezentje V, Swen J, Moes DJAR, Bohringer S, Batman E, van Druten E, Smorenburg C, van Bochove A, Zeillemaker A, Jongen L, Los M, Neven P, Gelderblom H, Guchelaar HJ. Tamoxifen Pharmacogenetics and Metabolism: Results From the Prospective CYPTAM Study. J Clin Oncol. 2019 Mar 10;37(8):636-646. doi: 10.1200/JCO.18.00307. Epub 2019 Jan 24.
• Background Lu J, Li H, Guo P, Shen R, Luo Y, Ge Q, Shi W, Li Y, Zhu W. The effect of CYP2D6 *10 polymorphism on adjuvant tamoxifen in Asian breast cancer patients: a meta-analysis. Onco Targets Ther. 2017 Nov 13;10:5429-5437. doi: 10.2147/OTT.S149197. eCollection 2017.

Drugs

Indications